Online Powder Polymer Injection System and Method for Fracturing and Stimulating Oil and Gas Wells

Abstract

This invention relates to the field of oil and gas well fracturing technology, and discloses an online injection system and method for powdered polymers used in oil and gas well fracturing. The system includes a vehicle-mounted mixing equipment, a transfer tank, and a PLC control system. The PLC control system is connected to the vehicle-mounted mixing equipment and the transfer tank. The vehicle-mounted mixing equipment mixes the powdered polymer with a chemical mixing liquid to form a thickener suspension that can be added online. The vehicle-mounted mixing equipment includes a dispersion tank, a liquid tank, and a powder tank. The transfer tank is connected to the dispersion tank, and the upper part of the transfer tank is connected to the dispersion tank. A negative pressure feed valve is installed on a second branch pipe. The upper part of the liquid tank is connected to a liquid container. The transfer tank is connected to the lower part of the liquid tank via a second centrifugal pump. A variable frequency rotor pump is connected to the transfer tank via a pipeline. The variable frequency rotor pump is connected to a sand mixing truck via a fourth pipeline. The method includes a preparation stage and a mixing stage. It can optimize construction technology, improve liquid performance, save project costs, and achieve safety and environmental protection. The powdered polymer exhibits good dispersion uniformity and high hydration efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wellbore engineering in oil and gas exploration and development, especially shale oil and gas exploration and development, and particularly relates to a powder polymer online injection system and method for oil and gas well fracturing reconstruction. BACKGROUND

[0002] Oil and gas well fracturing reconstruction is a wellbore engineering technology frequently used in the process of oil and gas exploration and development. Through fracturing reconstruction of oil and gas reservoirs, the purpose of increasing the yield of oil and gas wells is achieved. In the process of oil and gas well fracturing reconstruction, scientific and engineering technologies in three aspects of machinery, chemistry, and mathematical model are usually involved. The machinery aspect includes high-pressure pumping equipment, sand mixing trucks, instrument and meter trucks, etc., the chemistry aspect includes fracturing fluid and additives and proppants, and the mathematical model aspect includes fracturing design software. Powder polymer is often used in the fracturing process to achieve the purposes of increasing the viscosity, reducing the resistance, and carrying sand of working fluid. Oil and gas well fracturing reconstruction refers to a method of improving oil and gas production by reconstructing oil and gas reservoirs through fracturing process engineering technology. Mixing and adding refer to an engineering process method of continuously feeding fracturing fluid additives and proppants into the wellbore through special mechanical equipment and process at the fracturing construction site.

[0003] Polymer is the main additive in the fracturing fluid system. By adding polymer in the fracturing fluid, the viscosity of the fracturing fluid at well temperature is maintained, the fracturing fluid is diverted, the resistance in the pumping process is reduced, and the liquid sand carrying performance is improved.

[0004] How to mix and add polymer in the process of field construction has a great influence on the economy and reconstruction effect of oil and gas well fracturing reconstruction process. At present, two ways of mixing and adding polymer are mainly used in field construction, namely batch mixing and continuous method. The batch mixing method is to first hydrate the powder in the fracturing fluid tank and add other additives before fracturing construction, and then pump the prepared fracturing fluid in the fracturing fluid tank to the sand mixing truck through the low-pressure pump truck during fracturing construction. The continuous method refers to mixing and adding powder or liquid polymer, water, and other additives in real time through special or conventional transfer equipment during the fracturing construction process and adding them to the sand mixing truck. The two mixing and adding methods currently have the following problems, which can be seen in CN 108659809A, 2018.10.16 "A concentrated liquid preparation method based on continuous fracturing":

[0005] The batch mixing method divides the entire fracturing construction process into two parts, on the one hand, it needs to increase additional equipment, personnel and other logistical support measures, on the other hand, it will greatly extend the construction time, making the entire oil and gas reservoir fracturing cost increase, efficiency reduction. Especially in recent years, the fracturing of shale oil and gas reservoirs, the single well transformation scale (horizontal well staged fracturing) is several to dozens of times the scale of traditional fracturing (straight well single layer), such fracturing process due to the complexity of the process program, low operation efficiency, it is almost impossible to use the traditional liquid batch mixing method, see CN 108659809 A.

[0006] The current continuous mixing and transfer method mainly has two situations, the most commonly used is to form a liquid product by adding polymer additives, such as inverse (water-in-oil) polymer emulsion produced by emulsion polymerization, or a thickener suspension formed by suspending a powder polymer in an oil phase or other liquid solvent. During the fracturing operation, the corresponding liquid transfer pump is used to directly transfer these liquid polymers to the sand mixing truck, see CN 108659809 A.

[0007] The water-in-oil inverse emulsion polymer contains a large amount of other additives (such as oil phase and surfactant), which helps to maintain the stability of the emulsion to some extent, but results in a relatively low effective ingredient (generally 30%). In addition, the polymer obtained by inverse emulsion polymerization usually has a low molecular weight, which makes the amount of thickener used larger in actual application, especially when using high salinity water to prepare the fracturing fluid, the performance of the prepared fracturing fluid is poor, see CN 116179180 A, 2023.05.30 "A clean concentrated fracturing fluid based on water-soluble polymer".

[0008] For oil-based suspensions, the main components contain a large amount of mineral oil, stabilizers and surfactants, etc. The stabilizer is usually water-insoluble organic bentonite, nanomaterials, etc. The surfactant is usually a non-ionic surfactant, such as the Span and Tween series. The presence of mineral oil not only increases the cost, but also causes potential damage to storage equipment and the formation. The insoluble stabilizers such as organic bentonite are difficult to dissolve in water, which affects the uniformity and stability of the fracturing fluid. These insoluble substances may also be left in the formation, reducing the effective permeability of the formation and affecting the oil and gas production efficiency, which seriously limits the popularization and large-scale application of this technology. In addition, whether it is an inverse polymer emulsion or an oil-based suspension polymer product, due to the presence of a large amount of oil phase, not only does it greatly increase the cost of the liquid, but it also has a very negative impact on environmental protection, and it also causes potential damage to the reservoir, affecting the effective permeability of the reservoir, see CN 116179180 A.

[0009] In recent years, aqueous solvent-based suspensions have gained attention, however, similar to oil-based suspensions or inverse emulsion polymers, a large amount of solvents such as polyethylene glycol, methanol, ethanol, etc. are used in the design of aqueous solvent-based products instead of the oil phase of oil-based suspensions, see CN 111394085 A, 2020.07.10, "A high content aqueous drag reducer and its preparation method". The addition of a large amount of solvents not only has a negative impact on environmental protection, but also causes other technical and economic problems. From the aspect of stability, particles in the suspension are prone to sedimentation and agglomeration. This is because the interaction between the particles and the dispersion medium is not strong enough to effectively resist the force of gravity and the attraction between particles. In some solvent-based thickening agent suspensions, polymer particles may gradually sink due to their own high density or surface properties after standing for a period of time, resulting in uneven concentration of the suspension from top to bottom, affecting the consistency of its performance. Moreover, particles may agglomerate together due to van der Waals forces and other interactions, forming larger aggregates, further damaging the stability of the suspension and reducing the dispersion of its active ingredients, thereby affecting its effect in the oil and gas production process. In terms of solubility, some components in solvent-based suspensions may have poor solubility. For example, some additives or polymers have a slow dissolution rate in water and require a long stirring time or special treatment to completely dissolve. This not only increases the complexity and time cost of operation, but also may result in the inability to achieve the expected performance effect in actual application. In the application scenario of fracturing fluid, if the key thickening agent or drag reducer component cannot be quickly dissolved, it will affect the immediate performance of the fracturing fluid, such as the increase in viscosity and the exertion of drag reduction effect, thereby adversely affecting the efficiency of oil and gas production. In terms of cost, the preparation and use of solvent-based suspensions are relatively high. On the one hand, in order to maintain the stability of the suspension, some expensive stabilizers or surfactants may need to be added, which increases the cost of raw materials. On the other hand, due to the above-mentioned solubility and stability problems, more complex production processes and equipment may be required to ensure the quality of the suspension, which also leads to an increase in production costs. In large-scale oil and gas production operations, these cost increases will have a greater impact on economic benefits, limiting the widespread application and promotion of solvent-based suspensions.

[0010] A novel mixing and transfer technology has been reported, which utilizes specialized equipment to directly mix powdered polymers and water on-site (typically to prepare a pre-mixed solution of approximately 2% concentration) and transfer it to a sand mixing truck. Theoretically, this technology not only achieves continuous mixing, thereby improving operational efficiency, but also avoids the increased costs and environmental impact associated with using liquid emulsions or suspensions, making it a promising new method for continuous mixing and transfer. However, fatal flaws have been discovered during field implementation. On the one hand, when the powdered polymer is pre-mixed into a 2% solution in water, it easily forms fisheyes, significantly reducing product efficiency. On the other hand, the polymer aqueous solution dissolved in water rapidly forms highly viscous colloidal substances. These semi-solid colloids, when transferred to the sand mixing truck for further hydration and mixing with other additives, not only exhibit poor dispersion and solubility but also pose a risk of clogging pipelines, downhole tools, and reservoirs. Summary of the Invention

[0011] This invention aims to overcome the shortcomings of existing technologies by providing an online powder polymer injection system for oil and gas well fracturing. This invention enables online mixing, addition, and transfer of the required powder polymer, achieving optimized construction processes, improved fluid properties, reduced project costs, and enhanced safety and environmental protection. It also solves the problems of poor powder dispersion uniformity and low hydration efficiency found in existing technologies.

[0012] The present invention also provides an online injection method for powder polymers used in oil and gas well fracturing.

[0013] The technical solution adopted by this invention to solve its technical problem is:

[0014] An online powder polymer injection system for fracturing oil and gas wells includes a mixing device, which comprises a vehicle-mounted mixing unit, a transfer tank, and a PLC control system. The PLC control system is connected to the vehicle-mounted mixing unit and the transfer tank. The vehicle-mounted mixing unit mixes the powder polymer with a chemical mixing liquid to form a thickener suspension that can be added online. The vehicle-mounted mixing unit includes a dispersion tank, a liquid tank, and a powder tank. The transfer tank is connected to the dispersion tank via a main pipeline, a branch pipeline one, and a centrifugal pump one. The transfer tank is connected to the upper part of the dispersion tank via a main pipeline and a branch pipeline two. A negative pressure feed valve is installed on the branch pipeline two. The upper part of the liquid tank is connected to a liquid drum tank via a delivery pump and pipeline. The transfer tank is connected to the lower part of the liquid tank via a main pipeline, a branch pipeline three, and a centrifugal pump two. A flow control valve is installed on the branch pipeline three. A variable frequency rotor pump is connected to the transfer tank via a pipeline. The variable frequency rotor pump is connected to a sand mixing truck via a pipeline four, and a flow meter is installed on the pipeline four.

[0015] The powder container is used to store powder polymers;

[0016] The liquid tank is used to store chemical mixtures pumped from liquid drum tanks;

[0017] The chemical mixture and powdered polymer are mixed in a dispersion tank to form a thickener suspension;

[0018] The transfer tank serves as an intermediate storage device, providing functions for the transfer and temporary storage of thickener suspension.

[0019] The dispersion tank is equipped with a stirrer and a negative pressure feed valve. During the mixing process, the chemical mixture and the powder polymer are fully mixed in the dispersion tank to form a uniform thickener suspension.

[0020] A centrifugal pump is connected to the lower part of the dispersion tank.

[0021] A stirrer is installed inside the liquid tank. A chemical mixture is added to the liquid tank and stirred by the stirrer to ensure that the chemical mixture is homogeneous.

[0022] The liquid tank is equipped with a liquid level display device.

[0023] The powder tank is equipped with an automatic bag-breaking device and an arch-breaking device. The automatic bag-breaking device completes the bag-breaking operation, allowing the powder polymer to fall smoothly into the tank. The arch-breaking device prevents the powder from clumping or bridging inside the tank, ensuring stable and smooth powder flow. The lower part of the powder tank is equipped with a screw conveyor device, which is connected to a compressed air pipeline. The screw conveyor device uses compressed air to transport the powder polymer through a negative pressure feed valve to the dispersion tank. The negative pressure feed valve utilizes the pressure difference principle of the Venturi effect to achieve the negative pressure feeding function. The screw conveyor device adopts a screw quantitative conveyor.

[0024] The weight ratio of the powder polymer to the chemical mixture is 20:80 to 60:40.

[0025] Powder polymers are synthetic polymers, or natural polymers and their derivatives.

[0026] The chemical mixture is mainly composed of additives associated with fracturing fluids, including one or more of clay stabilizers, bactericides, and drainage aids.

[0027] The clay stabilizer is a quaternary ammonium compound.

[0028] Depending on the type of powder polymer, an aqueous inhibitor is added to the chemical mixture;

[0029] The aqueous inhibitors are water-soluble salts, cationic polymers and cationic surfactants, as well as organic solvents or combinations thereof.

[0030] A method for online injection of powdered polymers for fracturing oil and gas wells, utilizing the aforementioned online injection system for powdered polymers for fracturing oil and gas wells, involves mixing the powdered polymer with a chemical mixing solution in a dispersion tank via a negative pressure feed valve. The mixture is then dispersed by a stirrer within the dispersion tank to form a uniformly dispersed thickener suspension. This suspension is then directly transferred to a sand mixing truck via a variable frequency rotor pump in a transfer tank, where it is mixed with water and other additives to form a fracturing fluid. The method includes the following steps:

[0031] 1) Preparation stage

[0032] The preparation phase includes the storage of liquid materials and the storage of powdered polymers;

[0033] 2) Mixing stage

[0034] The mixing stage includes starting the cycle and forming negative pressure, premixing and conveying the powder polymer, continuous mixing and material replenishment, initial dispersion and storage of the thickener suspension, completion of work preparation, and pumping of the thickener suspension for use.

[0035] The storage of liquid materials and powdered polymers specifically includes the following steps:

[0036] Liquid material storage: Use a transfer pump to transfer the chemical mixture from the on-site liquid drum to the liquid tank; during the transfer process, pay attention to the liquid level display device on the liquid tank, and stop the transfer of the chemical mixture when the liquid level reaches the preset designated position; after the transfer is completed, if other additives need to be added according to the process requirements, start agitator one, add the additives according to the specified addition order and dosage, and continue to stir for a period of time to make the additives fully and evenly mixed with the liquid material;

[0037] Powder polymer storage: A suitable number of powder polymer ton bags are hoisted to the bag-breaking device on the top of the powder tank for automatic bag breaking; the bag-breaking device is activated to precisely cut the powder polymer ton bags, allowing the powder polymer to fall naturally into the powder tank; during the powder storage process, the anti-bridging device built into the powder tank remains open, continuously acting on the powder to prevent the powder from clumping or bridging due to moisture or static electricity, ensuring that the powder is always in a loose state and can flow out smoothly to participate in subsequent mixing;

[0038] The process of starting the cycle and forming negative pressure, premixing and conveying the powder polymer, continuous mixing and material replenishment, initial dispersion and storage of the thickener suspension, completion of work preparation, and pumping of the thickener suspension for use specifically includes the following steps:

[0039] To initiate circulation and create negative pressure, pump an appropriate amount of chemical mixture from the liquid tank into the dispersion tank and start the circulation system of the dispersion tank. After the circulation system is running, a negative pressure environment will be generated at the negative pressure feed valve due to the high-speed flow of the chemical mixture, creating conditions for the subsequent intake of powder polymer.

[0040] Powder polymer premixing and conveying: Turn on the screw conveyor to transport the powder polymer in the powder tank to the dispersion tank; monitor the weight of the conveyed powder polymer in real time during the conveying process, and stop the screw conveyor when the required weight of powder polymer for premixing is reached;

[0041] Continuous mixing and material replenishment: The chemical mixing solution is continuously pumped or self-circulated from the liquid tank to the dispersion tank according to the designed discharge rate, ensuring thorough mixing of the chemical mixing solution and powdered polymer within the dispersion tank for continuous mixing. During mixing, the material levels in both the liquid and powder tanks are monitored. When the liquid level in the liquid tank approaches its lower limit or the powder level in the powder tank is insufficient, replenishment is performed. When replenishing liquid, the material storage operation of the chemical mixing solution in the preparation stage is repeated. When replenishing powder, the powdered polymer ton bags are hoisted to the bag-breaking device in the powder tank for bag breaking and feeding.

[0042] Preliminary dispersion and storage of thickener suspension: After continuous mixing begins, the thickener suspension in the dispersion tank is continuously pumped to the transfer tank through pipelines. In the transfer tank, the thickener suspension continues to disperse, improving its uniformity and stability.

[0043] Work preparation complete: When the liquid level in the transfer tank reaches the designated position, it indicates that the thickener suspension required for on-site operations has been prepared in sufficient quantities. At this time, the condition of all equipment and materials meets the operational requirements, and on-site operations can begin.

[0044] Thickener suspension pumping: Turn on the variable frequency rotor pump and precisely control the flow rate according to the design displacement to pump the thickener suspension in the transfer tank to the sand mixing truck; during the pumping process, continuously monitor the operating parameters of the variable frequency rotor pump to ensure stable operation and ensure that the flow rate and pressure of the delivered thickener suspension meet the usage requirements of the sand mixing truck, so as to provide a stable material supply for subsequent construction operations.

[0045] The beneficial effects of this invention are:

[0046] 1. The present invention relates to an online mixing and addition device and method for powdered polymers used in oil and gas well fracturing, which utilizes the structure and working principle of a negative pressure feed valve and a rapid dispersion agitator to fully mix powdered polymers with chemical mixing liquids (instead of water) in a short time, forming a uniformly dispersed pure water-based low-viscosity thickener suspension. This ensures high efficiency and uniformity in mixing, achieving uniform dispersion and rapid hydration effects that are difficult to achieve with traditional mixing methods. The present invention enables online mixing, addition, and transfer of the required powdered polymers, optimizing construction processes, improving liquid properties, saving project costs, and achieving safety and environmental protection. It also solves the problems of poor powder dispersion uniformity and low hydration efficiency in existing technologies: namely, in existing technologies, whether traditional batch mixing or on-site continuous powder mixing techniques, it is difficult to achieve rapid and uniform dispersion and hydration when mixing powdered polymers with water and additives, resulting in low product utilization efficiency, the need for additional special equipment, increased overall operating costs, and potential operational risks and formation damage.

[0047] 2. The chemical mixture in this invention comprises quaternary ammonium compounds and aqueous inhibitors. Quaternary ammonium compounds may play an important role in the mixture, helping to improve the chemical properties of the system, such as enhancing compatibility with other substances or promoting specific chemical reactions. Aqueous inhibitors can suppress certain unwanted reactions or phenomena in the system, such as preventing the hydrolysis or precipitation of certain substances, thereby ensuring the stability and effectiveness of the entire mixture in terms of physical and chemical properties, solving the problems of poor uniformity of mixing and dispersion and poor rapid hydration performance in existing technologies.

[0048] 3. This invention, through precise design and flow control of the negative pressure feed valve and the rapid dispersing agitator, can accurately control the ratio of powdered polymer to chemical mixing solution, ensuring that the suspension formed in each mixing process has stable performance and meets technical and design requirements. It solves the problem of significant errors in ratio control and stability in existing online powder mixing and transfer technologies, which are prone to affecting the final performance of fracturing fluid due to fluctuations in the mixing ratio, thus ensuring the reliability and stability of fracturing operations.

[0049] 4. This invention utilizes a simple negative pressure feed valve and a rapid dispersing agitator to achieve online addition and instant mixing. At the construction site, the powder is mixed with the chemical mixing liquid mentioned in this invention, and then pumped to a sand mixing truck by a variable frequency rotor pump via a transfer tank to mix with water to form fracturing fluid. This eliminates the need for large-scale premixing and additional special equipment, greatly simplifying equipment and operational procedures, reducing construction costs, improving work efficiency, reducing construction risks, and enhancing the convenience and efficiency of on-site operations. It solves the problem that traditional powder batch mixing methods require additional complex premixing equipment and long mixing times, failing to meet the needs of rapid on-site construction, especially in shale oil and gas development fracturing operations in recent years.

[0050] 5. This invention eliminates the expensive oils and solvents used to achieve the liquefaction of powdered polymers, significantly reducing the cost of fracturing fluid systems. Furthermore, the accompanying chemical mixing fluid used in this invention employs pure water-based, environmentally friendly additives found in the fracturing fluid itself, exhibiting excellent environmental performance and further reducing the cost of fracturing fluid systems. It has no side effects on environmental protection and addresses the issue that existing fracturing operations primarily use liquid polymer products, including reverse emulsions, oil-based or solvent-based suspensions. While these products and technologies have addressed some of the difficulties in dispersing and hydrating powdered polymer products and the complexity of equipment processes, they also suffer from drawbacks such as significantly increased fluid costs and negative environmental impacts. This invention solves the problems of high cost and environmental unfriendliness associated with currently widely used liquid polymer products.

[0051] 6. In the field of wellbore engineering technology for oil and gas reservoir fracturing and stimulation, this invention innovatively proposes a novel online powder polymer injection system and method. It cleverly integrates both chemical and mechanical technologies, breaking through the limitations of current methods that rely on only a single approach (mechanical or chemical), thereby solving various technical, economic, and environmental problems caused by using a single method.

[0052] In terms of chemical mechanism, this invention involves the analysis and utilization of the chemical properties of polymer dry powder and chemically mixed liquid, ensuring that appropriate physicochemical reactions occur between the components during the mixing and addition process, thereby improving the technical, economic and environmental performance of the final product.

[0053] In terms of mechanical equipment and processes, this invention utilizes a carefully designed negative pressure feeding device and a high-speed dispersing agitator, taking advantage of their unique fluid dynamics principles, to achieve efficient mixing, dispersion, and transfer of polymer dry powder and chemical compound liquid.

[0054] This invention effectively combines chemical and mechanical technologies to achieve precise and efficient online mixing and addition of polymer dry powder during fracturing operations. This not only improves the convenience and efficiency of operations and allows for precise control of additive mixing and final product performance, but also provides a reliable technical approach for field operations of oil and gas reservoir fracturing and stimulation that features superior fracturing fluid performance, low operating costs, low construction risks, and is more environmentally friendly. Attached Figure Description

[0055] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0056] Figure 1 This is a schematic diagram of the online powder polymer dispensing system of the present invention;

[0057] Figure 2 These are stability images from preparation example 3 of the present invention;

[0058] Figure 3 These are hydration curve images of Preparation Example 3 and Comparative Examples 1 and 2 of the present invention;

[0059] Figure 4 Images showing the temperature and shear resistance of the crosslinked fracturing fluids prepared in Example 3 and Comparative Example 1 of this invention;

[0060] Figure 5 The image shows the clay stability performance of preparation example 4 of the present invention.

[0061] In the diagram, there are: 1. Transfer tank; 2. Dispersion tank; 3. Liquid tank; 4. Powder tank; 5. Centrifugal pump 1; 6. Negative pressure feed valve; 7. Flow control valve; 8. Centrifugal pump 2; 9. Screw conveyor; 10. Liquid drum tank; 11. Bag breaking device; 12. Arch breaking device; 13. Agitator 1; 14. Agitator 2; 15. Main pipeline; 16. Branch pipeline 1; 17. Branch pipeline 2; 18. Branch pipeline 3; 19. Variable frequency rotor pump; 20. Conveying pump; 21. Compressed air pipeline; 22. Powder polymer ton bag; 23. Flow meter. Detailed Implementation

[0062] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0063] Example 1

[0064] like Figures 1-5As shown, an online powder polymer injection system for oil and gas well fracturing includes a mixing device, which comprises a vehicle-mounted mixing unit, a transfer tank 1, and a PLC control system. The PLC control system is connected to the vehicle-mounted mixing unit and the transfer tank 1. The vehicle-mounted mixing unit mixes the powder polymer with a chemical mixing liquid to form a thickener suspension that can be added online. The vehicle-mounted mixing unit includes a dispersion tank 2, a liquid tank 3, and a powder tank 4. The transfer tank 1 is connected to the dispersion tank 2 via a main pipeline 15, a branch pipeline 16, and a centrifugal pump 5. The transfer tank 1 is also connected to the upper part of the dispersion tank 2 via the main pipeline 15 and a branch pipeline 17. A negative pressure feed valve 6 is provided on the branch pipeline 17. The upper part of the liquid tank 3 is connected to the liquid drum tank 10 via a transfer pump 20 and a pipeline. The transfer tank 1 is connected to the lower part of the liquid tank 3 via a main pipeline 15, a third branch pipeline 18, and a second centrifugal pump 8. A flow control valve 7 is installed on the third branch pipeline 18. A variable frequency rotor pump 19 is connected to the transfer tank 1 via a pipeline. The variable frequency rotor pump 19 is connected to the sand mixing truck via a fourth pipeline. A flow meter 23 is installed on the fourth pipeline. The negative pressure feed valve 6 uses the pressure difference principle of the Venturi effect to realize the negative pressure feed function.

[0065] The powder tank 4 is used to store powdered polymers. The powder tank 4 is equipped with an automatic bag-breaking device 11 and an arch-breaking device 12. The automatic bag-breaking device 11 automatically breaks the bag after the polymer in the ton bag 22 is lifted to the designated position by a crane, allowing the powdered polymer to fall smoothly into the tank. The arch-breaking device 12 effectively prevents the powder from clumping or bridging inside the tank, ensuring a stable and smooth flow of powder. A screw conveyor 9 is located at the bottom of the powder tank 4. The screw conveyor 9 is a screw metering conveyor connected to a compressed air pipeline 21. The screw metering conveyor uses compressed air to transport the powdered polymer through a negative pressure feed valve 6 to the dispersion tank 2.

[0066] The liquid tank 3 is used to store the chemical mixture pumped from the on-site liquid drum tank 10. The liquid tank 3 is equipped with a stirrer 13, which ensures that the liquid material composition is uniform through the stirring function of the stirrer 13.

[0067] The liquid tank 3 is equipped with a liquid level display device.

[0068] The dispersion tank 2 is equipped with a second stirrer 14 and a negative pressure feed valve 6. It is a key mixing area. During the mixing process, a series of operations are performed to fully mix the chemical mixture with the powdered polymer to form a uniform thickener suspension. The first stirrer 13 is a paddle stirrer, and the second stirrer 14 is a dispersion disc stirrer. A centrifugal pump 5 is connected to the lower part of the dispersion tank 2.

[0069] The transfer tank 1, as an intermediate storage device, can be flexibly arranged according to the actual needs on site, providing more convenient material transfer and temporary storage functions for the entire mixing process.

[0070] The weight ratio of the powder polymer to the chemical mixture is 20:80 to 60:40.

[0071] Preferably, the weight ratio of the powder polymer to the chemical mixture is 30:70 to 50:50.

[0072] Powdered polymers are synthetic polymers, or natural polymers and their derivatives. For example, powdered polymers are artificially synthesized polymers, such as polyacrylamide homopolymers and copolymers; or natural plant gums and their derivatives, such as guar gum and its derivatives, starch and its derivatives; or polymers prepared by biological methods, such as xanthan gum or hummus gum.

[0073] The chemical mixture is mainly composed of additives associated with fracturing fluid, including one or more of clay stabilizers, bactericides, and drainage aids. The chemical mixture is added to the liquid tank 3 as needed, and the stirring function of the stirrer 13 ensures that the chemical mixture with added additives has a uniform composition.

[0074] The clay stabilizer is a quaternary ammonium compound, such as ammonium chloride, choline chloride, tetramethylammonium chloride, etc. A high concentration of quaternary ammonium compound solution can inhibit polymer hydration. After the powdered polymer is mixed with a high concentration of quaternary ammonium compound at the well site, a uniform thickener suspension is formed. When this suspension is mixed with a large amount of water, the quaternary ammonium compound is fully diluted, and the polymer will hydrate completely and rapidly.

[0075] The weight fraction of quaternary ammonium compounds is 40%-100%. Preferably, the weight fraction of quaternary ammonium compounds can be 50%-70%.

[0076] The quaternary ammonium compound is a monoquaternary ammonium compound, a bisquaternary ammonium compound, a polymeric quaternary ammonium compound, or a combination thereof.

[0077] The quaternary ammonium compound is preferably a salt, comprising quaternary ammonium cation and anion moieties.

[0078] The anionic portion is a halide, such as a fluoride, chloride, bromide, or iodide; salicylate; oxalate; bicarbonate; tartrate; citrate; carbonate; dihydrogen citrate; nitrate; nitrite; phosphate; sulfate; sulfonate.

[0079] The anionic portion is preferably selected from halides, such as chlorides.

[0080] Preferably, the cation of the quaternary ammonium compound is selected from choline, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, and imidazoline.

[0081] The quaternary ammonium compound is choline chloride, tetramethylammonium chloride, tetraethylammonium chloride, and tetrapropylammonium chloride. Preferably, the quaternary ammonium compound is choline chloride and tetramethylammonium chloride.

[0082] The quaternary ammonium compounds mentioned are typically choline chloride solution or tetramethylammonium chloride solution. The choline chloride solution is typically a 75 wt.% aqueous solution. The tetramethylammonium chloride solution is typically a 50 wt.% aqueous solution.

[0083] Depending on the type of powder polymer, an aqueous inhibitor is added to the chemical mixture.

[0084] The aqueous inhibitor has a weight fraction of 1-40%. Preferably, the aqueous inhibitor has a weight fraction of 1-10%.

[0085] The aqueous inhibitors are water-soluble salts, cationic polymers and cationic surfactants, as well as organic solvents or combinations thereof.

[0086] The water-soluble salts include water-soluble metal salts and ammonium salts, such as barium chloride, sodium chloride, sodium acetate, potassium chloride, calcium nitrate, calcium acetate, calcium chloride, magnesium sulfate, magnesium nitrate, and ammonium sulfate.

[0087] The cationic polymer and surfactant are cationic polyacrylamide, polydimethyldiallylammonium chloride, hexadecyltrimethylammonium bromide, etc. The organic solvent is methanol, ethanol, dimethylformamide, dimethylacetamide, acetone, etc.

[0088] Example 2

[0089] A method for online injection of powdered polymers for fracturing oil and gas wells involves using an online powdered polymer injection system. The powdered polymer is mixed with a chemical mixing solution in a dispersion tank 2 via a negative pressure feed valve, and then dispersed by a high-speed dispersion disc to form a uniformly dispersed thickener suspension. This suspension is then directly transferred to a sand mixing truck to be mixed with water and other additives to form fracturing fluid. The weight ratio of the powdered polymer to the chemical mixing solution is 20:80. The method includes the following steps:

[0090] 1) Preparation stage

[0091] The preparation stage includes liquid material storage and powder polymer storage; specifically, it includes the following steps:

[0092] Liquid material storage: The chemical mixture in the on-site liquid drum 10 is transferred to liquid tank 3 using the transfer pump 20. During the transfer process, the liquid level display device on liquid tank 3 is closely monitored. When the liquid level reaches the preset designated position, the transfer of the chemical mixture is stopped. After the transfer is completed, if other additives need to be added according to process requirements, the agitator 13 can be started, and the additives are added in the prescribed order and dosage. The agitator is continuously stirred for a period of time to ensure that the additives are fully and evenly mixed with the chemical mixture.

[0093] Powder polymer storage: A suitable number of powder polymer ton bags are smoothly lifted by a crane to the bag-breaking device 11 on the top of the powder tank 4 for automatic bag breaking; the bag-breaking device is activated to precisely cut the powder polymer ton bags, allowing the powder polymer to fall naturally into the powder tank 4; during the powder storage process, the arch-breaking device 12 remains open, and the arch-breaking device 12 continuously acts on the powder through mechanical vibration, airflow disturbance, etc., to prevent the powder from clumping or bridging due to moisture, static electricity, etc., ensuring that the powder is always in a loose state and can flow out smoothly at any time to participate in subsequent mixing.

[0094] 2) Mixing stage

[0095] The mixing stage includes starting the circulation and establishing negative pressure, premixing and conveying the powder polymer, continuous mixing and material replenishment, initial dispersion and storage of the thickener suspension, completion of work preparation, and pumping of the thickener suspension for use. Specifically, it includes:

[0096] Start the circulation and create negative pressure: Pump an appropriate amount of liquid from liquid tank 3 into dispersion tank 2 and start the circulation system of dispersion tank; after the circulation system is running, a negative pressure environment will be generated at the negative pressure feed valve due to the high-speed flow of chemical mixture, which creates conditions for the subsequent intake of powder polymer.

[0097] Powder polymer premixing and conveying: Turn on the screw conveyor 9 to slowly and evenly convey the powder polymer in the powder tank 4 to the dispersion tank 2; during the conveying process, monitor the weight of the conveyed polymer in real time through an electronic scale or other metering equipment, and stop the screw conveyor 9 when the required polymer weight for premixing is reached.

[0098] Continuous mixing and material replenishment: Liquid or self-circulating liquid is continuously pumped from liquid tank 3 to dispersion tank 2 according to the designed discharge rate, ensuring thorough mixing of the chemical mixture and powdered polymer within the dispersion tank, achieving continuous mixing. The liquid can be pumped to transfer tank 1. During the mixing process, due to continuous material consumption, the liquid levels in liquid tank 3 and powder tank 4 must be closely monitored. When the liquid level in liquid tank 3 approaches its lower limit or the powder content in powder tank 4 is insufficient, replenishment should be carried out promptly. When replenishing liquid, the liquid material storage operation from the preparation stage is repeated. When replenishing powder, a crane is used again to lift the powdered polymer ton bags to the bag-breaking device 11 in powder tank 4 for bag breaking and feeding.

[0099] Preliminary dispersion and storage of thickener suspension: After continuous mixing begins, the thickener suspension in the dispersion tank is continuously pumped to transfer tank 1 through pipelines. In transfer tank 1, the thickener suspension continues to disperse, further improving its uniformity and stability.

[0100] Work preparation complete: When the liquid level in transfer tank 1 reaches the designated position, it indicates that the thickener suspension required for on-site operations has been prepared in sufficient quantities. At this time, the status of all equipment and materials meets the operational requirements, and on-site operations can begin.

[0101] Thickener suspension pumping: Turn on the variable frequency rotor pump 19 and precisely control the flow rate according to the design displacement to pump the thickener suspension in the transfer tank 1 into the sand mixing truck; during the pumping process, continuously monitor the operating parameters of the variable frequency rotor pump to ensure its stable operation and ensure that the flow rate and pressure of the conveyed thickener suspension meet the usage requirements of the sand mixing truck, so as to provide a stable material supply for subsequent construction operations.

[0102] This equipment integrates all the above operations into a PLC control system, achieving automated continuous production through pre-written programs. The PLC control system can monitor the operating status of each piece of equipment, material level, flow rate, pressure, and other parameters in real time. In case of any abnormality, it can promptly issue alarms and take appropriate measures, greatly improving production efficiency and the safety and stability of the production process.

[0103] This invention mixes powdered polymer with a chemical mixing liquid via a negative pressure feed valve to form a uniformly dispersed thickener suspension. This suspension is then directly transferred to a fracturing truck and mixed with water and other additives to form a fracturing fluid. This invention combines the chemical mixing liquid with the powdered polymer to create a thickener suspension system with high chemical and physical stability.

[0104] The following are examples and comparative examples of the present invention prepared in the laboratory according to the procedure of Example 2:

[0105] Example 3

[0106] 53 parts by weight of 75% choline chloride solution, 5 parts by weight of dimethylformamide, and 2 parts by weight of calcium acetate were added to a stirrer and mixed thoroughly. Then, 40 parts by weight of anionic polyacrylamide were added and mixed thoroughly to obtain a water-based thickener suspension with a polyacrylamide content of 40 wt.%. The weight ratio of the powder polymer to the chemical mixture was 40:60.

[0107] Example 4

[0108] 30 parts by weight of 75% choline chloride solution, 7 parts by weight of anhydrous ethanol, and 3 parts by weight of magnesium sulfate were added to a stirrer and mixed thoroughly. Then, 60 parts by weight of anionic polyacrylamide were added and mixed thoroughly to obtain a water-based thickener suspension with a polyacrylamide content of 60 wt.%. The weight ratio of the powder polymer to the chemical mixture was 60:40.

[0109] Comparative Example 1

[0110] Add 57 parts by weight of the oil phase (No. 5 white oil) to the Wu Yin stirrer. After stirring, add 2 parts by weight of the suspending agent (organic clay) and 1 part by weight of the emulsifier (Span 80) and mix evenly. Then add 40 parts by weight of anionic polyacrylamide and mix evenly to obtain an oil-based thickener suspension with a polyacrylamide content of 40 wt.%.

[0111] Comparative Example 2

[0112] Add 98 parts by weight of tap water to Wu Yin's mixer, turn on the mixer and slowly add 2 parts by weight of anionic polyacrylamide. After mixing evenly, a thickener concentrate with a polyacrylamide content of 2 wt.% is obtained.

[0113] The following are experimental examples of the present invention.

[0114] 1. Experimental Methods

[0115] (1) Viscosity of the thickener suspension

[0116] Test method: The thickener suspension prepared in the example was preheated to 25°C, and then the apparent viscosity of the sample was measured according to the method in SY / T 7627.

[0117] (2) Stability of thickener suspension

[0118] Test method: The thickener suspension prepared in the example was loaded into a 100mL stoppered graduated cylinder, and the presence of free liquid was observed at 5, 20 and 60 minutes.

[0119] (3) Hydration curve

[0120] Test Method: A certain amount of deionized water was weighed and added to the Wu Yin stirrer. The stirring speed was set to 1000 RPM. Then, a certain amount of the example or comparative sample was quickly added (within 1 second) to make the content of anionic polyacrylamide in the solution 0.12 wt.%. After adding the sample, the mixture was stirred for 10 seconds and then stopped. In the next 10 seconds, the liquid in the stirring cup was transferred to the rotational viscometer slurry cup, and the slurry cup was installed. The rotational viscometer speed was set to 300 rpm. Starting from the 20th second after the sample was added, the rotational viscometer reading was taken, and then taken every 5 seconds until the reading stabilized. A hydration curve was plotted with time on the x-axis and the rotational viscometer reading on the y-axis.

[0121] (4) Temperature and shear resistance of cross-linked fracturing fluid

[0122] Test method: 98.9 parts by weight of tap water were added to a Wu Yin mixer. After stirring, 0.8 parts by weight of the sample from Example 3 or Comparative Example 1 were added. After stirring for 5 minutes, 0.3 parts by weight of the organozirconium crosslinking agent were added. After mixing for 2 minutes, stirring was stopped to obtain the crosslinked fracturing fluid. The fracturing fluid was measured at a temperature of 145℃ and a shear rate of 100s according to the method in SY / T 7627. -1 Viscosity value after 60 minutes of shearing.

[0123] (5) Drag reduction rate

[0124] Test method: The drag reduction rate of the solutions with a concentration of 0.1 wt.% in Example 3 and Comparative Example 1 was tested according to NB / T 14003.1.

[0125] (6) Clay stability performance

[0126] Test Method: Add 99.9 parts by weight of deionized water to a stirrer, then add 0.1 parts by weight of the example sample or 0.1 parts by weight of a 50% tetramethylammonium chloride solution. Mix thoroughly to obtain the test liquid. Add 4 mL of the test liquid to a 10 mL centrifuge tube, then add 0.5 g of bentonite powder, and finally add the test liquid to the 10 mL mark. Cap the centrifuge tube and shake vigorously 50 times (one round trip counts as one cycle). Let the centrifuge tube stand at room temperature for 2 hours. Then centrifuge at 1500 RPM for 15 minutes using an automatic balancing centrifuge. Remove the centrifuge tube and read the volume of bentonite at the bottom.

[0127] 2. Experimental Data

[0128] Table 1 Bulk viscosity data of the examples

[0129]

[0130] The water-based thickener suspensions prepared in Examples 3 and 4 have moderate bulk viscosity, which is beneficial for mixing and pumping in pumping equipment.

[0131] Table 2. Drag reduction data for Example 3 and Comparative Example 1

[0132]

[0133] The following is a detailed combination Figure 2 , Figure 3 , Figure 4 , Figure 5 Detailed explanation:

[0134] Combination Figure 2 The water-based thickener suspension prepared in Example 3 showed no sedimentation or free liquid generation within 60 minutes, demonstrating good stability.

[0135] Combination Figure 3 As can be seen from Example 3, Comparative Example 1, and Comparative Example 2, the water-based thickener suspension prepared in Example 3 does not require a demulsification process, has a fast hydration rate, disperses and hydrates rapidly after mixing with water, and has a short viscosity-inducing time. Furthermore, it does not contain the oil phase, organic clay, and surfactants found in Comparative Example 1. Therefore, the sample in Example 3 has a high drag reduction rate and reaches its maximum drag reduction rate in a short time.

[0136] The oil-based thickener suspension prepared in Comparative Example 1 is an oil-external phase suspension. After being mixed with water, it needs to go through the processes of dispersion, demulsification, and hydration. Therefore, the thickening time is long and the hydration rate is slow.

[0137] The 2 wt.% thickener concentrate prepared in Comparative Example 2 has a very high viscosity. It is difficult to disperse and hydrate evenly after mixing with water, and it is very easy to form "fish eyes". Therefore, its viscosity is low, and the unhydrated polymer will damage the formation.

[0138] Combination Figure 4 Compared with Comparative Example 1, the water-based thickener suspension prepared in Example 3 does not contain oil phase, suspending agent and surfactant that affect viscosity. Therefore, the crosslinked fracturing fluid prepared from the sample of Example 3 has higher viscosity.

[0139] Combination Figure 5 Example 4 not only contains choline chloride, a clay stabilizer commonly used in fracturing operations, but also contains polyacrylamide and water-based inhibitors that effectively inhibit clay swelling, thus exhibiting excellent clay stability. At the same dosage, its clay stability is even slightly superior to that of the commonly used clay stabilizer tetramethylammonium chloride.

[0140] This invention ensures that appropriate physicochemical interactions occur between the components during mixing and addition, thereby improving the technical, economic, and environmental performance of the final product.

[0141] This invention achieves efficient mixing, dispersion, and transfer of powdered polymers to the chemical liquid system of this invention through a negative pressure feed valve mixer and a high-speed dispersing agitator.

[0142] This invention enables precise and efficient online mixing and addition of powdered polymers during fracturing operations, improving operational convenience and efficiency, accurately controlling additive mixing and final product performance, and providing a reliable approach for field operations of oil and gas reservoir fracturing that features superior fracturing fluid performance, low operating costs, low construction risks, and is more environmentally friendly.

[0143] In the description of this invention, the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only to describe the invention and not to require the invention to be constructed or operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" in this invention should be interpreted broadly. For example, they can refer to a connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms based on the specific circumstances.

[0144] The above description represents preferred embodiments of the present invention. The specific embodiments are provided solely for a better understanding of the invention's concept. Those skilled in the art will recognize that various improvements or equivalent substitutions can be made based on the principles of the present invention, and these improvements or equivalent substitutions are also considered to fall within the scope of protection of the present invention.

Claims

1. An on-line powder polymer injection system for oil and gas well fracturing reconstruction, comprising a mixing device, the mixing device comprising a vehicle-mounted mixing equipment, a transfer tank, and a PLC control system, the PLC control system being connected with the vehicle-mounted mixing equipment and the transfer tank, and the vehicle-mounted mixing equipment mixing the powder polymer and chemical mixing liquid into a thickening agent suspension that can be added on-line, characterized in that, The vehicle-mounted mixing device comprises a dispersion tank, a liquid tank, a powder tank, and a transfer tank connected with the dispersion tank through a main pipeline, a first branch pipeline, and a centrifugal pump; the transfer tank is connected with the upper part of the dispersion tank through a main pipeline and a second branch pipeline, and a negative pressure feeding valve is arranged on the second branch pipeline; the upper part of the liquid tank is connected with a liquid barrel through a conveying pump and a pipeline; the lower part of the liquid tank is connected with the transfer tank through a main pipeline, a third branch pipeline, and a centrifugal pump; a flow control valve is arranged on the third branch pipeline; a variable frequency rotor pump is connected with the transfer tank through a pipeline; the variable frequency rotor pump is connected with the sand mixing vehicle through a fourth pipeline, and a flow meter is arranged on the fourth pipeline; The powder tank is used for storing the powder polymer. The liquid tank is used for storing the chemical mixing liquid pumped from the liquid barrel. The chemical mixing liquid and the powder polymer are mixed in the dispersion tank to form a suspending liquid of the thickening agent. The transfer tank is used as an intermediate storage device to provide the suspending liquid of the thickening agent with transfer and temporary storage functions. An automatic bag breaking device is arranged on the powder tank, and an arch breaking device is arranged on the powder tank; the automatic bag breaking device breaks the bag to allow the powder polymer to smoothly fall into the tank; the arch breaking device prevents the powder from caking and bridging in the tank to ensure that the powder stably and smoothly flows out; a screw conveying device is arranged at the lower part of the powder tank, and the screw conveying device is connected with a compressed air pipeline; the screw conveying device conveys the powder polymer to the dispersion tank through the negative pressure feeding valve by compressed air; the negative pressure feeding valve realizes the negative pressure feeding function by using the pressure difference principle of the Venturi effect; and the screw conveying device adopts a screw quantitative conveyor. The powder polymer is a synthetic polymer or a natural polymer and its derivative. The chemical mixing liquid mainly comprises additives associated with the fracturing fluid, and the additives include one or more of clay stabilizers, bactericides, and cleanup agents. The clay stabilizer is a quaternary ammonium compound. According to the type of the powder polymer, an aqueous inhibitor is added to the chemical mixing liquid. The aqueous inhibitor is a water-soluble salt, a cationic polymer, a cationic surfactant, and an organic solvent, or a combination thereof.

2. The in-line powder polymer injection system for oil and gas well fracturing according to claim 1, wherein, A stirrer two is arranged in the dispersion tank, and a negative pressure feeding valve is arranged on the dispersion tank; during the mixing process, the chemical mixing liquid and the powder polymer are fully mixed in the dispersion tank to form a uniform suspending liquid of the thickening agent. A centrifugal pump one is connected with the lower part of the dispersion tank.

3. The in-line powder polymer injection system for oil and gas well fracturing according to claim 2, wherein, A stirrer one is arranged in the liquid tank; the chemical mixing liquid is added to the liquid tank, and the stirrer one is used for stirring and ensuring that the chemical mixing liquid is uniform in composition. A liquid level display device is arranged on the liquid tank.

4. The powder polymer in-line dosing system for oil and gas well fracturing according to claim 1, characterized in that, The weight ratio of the powder polymer to the chemical mixing liquid is 20:80-60:

40.

5. A method for on-line powder polymer injection for oil and gas well fracturing reconstruction, characterized in that, The powder polymer is mixed with the chemical mixing liquid in the dispersion tank through the negative pressure feeding valve, and is dispersed by the stirrer two in the dispersion tank to form a uniformly dispersed suspending liquid of the thickening agent, and then the suspending liquid is directly transferred to the sand mixing vehicle by the variable frequency rotor pump of the transfer tank, and is mixed with water and other additives to form the fracturing fluid. 1) Preparation stage The preparation stage includes liquid material storage and powder polymer storage. 2) Mixing stage The mixing stage includes starting cycle and forming negative pressure, powder polymer premix conveying, continuous mixing and material supplement, thickening agent suspension preliminary dispersion storage, operation preparation completion, thickening agent suspension pumping use.

6. The method for on-line powder polymer dosing for oil and gas well fracturing reconstruction according to claim 5, characterized in that, The liquid material storage and powder polymer storage specifically include the following steps: Liquid material storage: use the delivery pump to deliver the chemical mixing liquid in the on-site liquid barrel to the liquid tank; during the delivery process, pay attention to the liquid level display device on the liquid tank, and stop the delivery of the chemical mixing liquid when the liquid level reaches the pre-set specified position; after the delivery is completed, if other additives need to be added according to the process requirements, start the stirrer one, add the additives in the specified order and dosage, and continuously stir for a period of time to make the additives and the liquid material fully mixed and uniform; Powder polymer storage: a proper amount of powder polymer ton bag is hoisted to the automatic bag breaking device at the upper part of the powder tank to break the bag; the bag breaking device is started to accurately break the powder polymer ton bag, so that the powder polymer falls into the powder tank naturally; during the powder storage process, the self-provided arch breaking device of the powder tank is kept in an open state, and the arch breaking device continuously acts on the powder to prevent the powder from caking or bridging due to moisture and static electricity, so as to ensure that the powder is always in a loose state and can flow out smoothly to participate in subsequent mixing; The starting cycle and forming negative pressure, powder polymer premix conveying, continuous mixing and material supplement, thickening agent suspension preliminary dispersion storage, operation preparation completion, thickening agent suspension pumping use specifically include the following steps: Starting cycle and forming negative pressure: pump an appropriate amount of chemical mixing liquid from the liquid tank to the dispersion tank, and open the circulation system of the dispersion tank; after the circulation system is running, a negative pressure environment is generated at the negative pressure feeding valve due to the high-speed flow of the chemical mixing liquid, which creates conditions for the subsequent suction of the powder polymer; Powder polymer premix conveying: open the screw conveying device to convey the powder polymer in the powder tank to the dispersion tank; monitor the weight of the conveyed powder polymer in real time during the conveying process, and stop the screw conveying device when the required powder polymer weight for premixing is reached; Continuous mixing and material supplement: continuously pump or self-circulate the chemical mixing liquid from the liquid tank to the dispersion tank according to the designed displacement, so that the chemical mixing liquid and the powder polymer are fully mixed in the dispersion tank to realize continuous mixing; during the mixing process, pay attention to the liquid levels in the liquid tank and the powder tank; when the liquid level in the liquid tank approaches the lower limit or the powder remaining amount in the powder tank is insufficient, supplement; when supplementing the liquid, repeat the operation of the chemical mixing liquid material storage in the preparation stage; when supplementing the powder, hoist the powder polymer ton bag to the bag breaking device of the powder tank again for bag breaking and feeding; Thickening agent suspension preliminary dispersion storage: after the continuous mixing starts, the thickening agent suspension in the dispersion tank is continuously pumped to the transfer tank through the pipeline, and the thickening agent suspension continues to be dispersed in the transfer tank to improve its uniformity and stability; Operation preparation completion: when the liquid level in the transfer tank reaches the specified position, it indicates that the thickening agent suspension required for the on-site operation has been prepared adequately, at this time, all equipment and material states meet the operation requirements, and the on-site operation starts; Pumping of the thickening agent suspension: start the variable frequency rotor pump, accurately control the flow according to the designed displacement, and pump the thickening agent suspension in the transfer tank into the sand mixing truck; during the pumping process, continuously monitor the operating parameters of the variable frequency rotor pump to ensure stable operation and ensure that the flow and pressure of the delivered thickening agent suspension meet the use requirements of the sand mixing truck, thereby providing stable material supply for subsequent construction operations.

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